Method and apparatus for constructing a monolithic silo

ABSTRACT

System for constructing concrete silos wherein molds are sequentially erected and filled as a three tiered mold unit with a crane scaffold supported on the top mold by radial arms which rest on ledges extending inwardly from the innerface thereof. The outer form of the bottom mold is then dismantled into semicircular sections, raised by using the three jib cranes of the crane scaffold and erected as the fourth tier. The inner form of the bottom mold is then dismantled in predetermined length sections for passage through the restricted space between the crane scaffold and the third tier and then erected to complete the fourth tier mold. The crane scaffold is then elevated by suspending it from the top of the fourth tier; the radial arms are then seated on the horizontal ledges of the fourth tier. A cart is rotatably mounted about the center post of the scaffold for evenly feeding concrete into the molds. Safety means are provided.

United States Patent 72] Inventors Richard L. Weaver, Route 1;

Benjamin K. Smoker, Route 3, both of Myerstown, Pa. [21] App1.No.720,687 [22] Filed Apr. 11, 1968 [45] Patented Nov. 9, 1971 [73]Assignee said Weaver, by said Smoker [54] METHOD AND APPARATUS FORCONSTRUCTING A MONOLITHIC SlLO 16 Claims, 24 Drawing Figs.

[52] US. Cl 264/32, 25/124, 25/130 A, 25/D1G. 26, 264/33 [51] lnt.ClE04b 1/16, E04h 7/22 [50] Field of Search 25/118 R, 130 A, 131 A, 131.5C, D10. 26, 124; 264/32, 33; 249/20, 22

[56] References Cited UNITED STATES PATENTS 908,326 12/1908 Polk 25/13025/ l 24 1,163,798 12/1915 Williams Primary Examiner-Robert F. WhiteAssistant Examiner-Jeffery R. Thurlow ABSTRACT: System for constructingconcrete silos wherein molds are sequentially erected and filled as athree tiered mold unit with a crane scaffold supported on the top moldby radial arms which rest on ledges extending inwardly from theinnerface thereof. The outer form of the bottom mold is then dismantledinto semicircular sections, raised by using the three jib cranes ofthecrane scaffold and erected as the fourth tier. The inner form of thebottom mold is then dismantled in predetermined length sections forpassage through the restricted space between the crane scaffold and thethird tier and then erected to complete the fourth tier mold. The cranescaffold is then elevated by suspending it from the top of the fourthtier; the radial arms are then seated on the horizontal ledges of thefourth tier. A cart is rotatably mounted about the center post of thescaffold for evenly feeding concrete into the molds. Safety means areprovided.

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RICHARD L WEAVER BENJAMIN K. SMOKER FIG. I4

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ATTORNEYS PAIENTEnunv 915m SHEET 2 OF 8 INVENTORS RICHARD L. WEAVERBENJAMIN K. SMOKER ATTORNEYS PATENTElluuv 9 I97! SHEET 3 BF 8 INVENTORSRICHARD L. WEAVER BENJAMIN K. SMOKER ATTORNEYS PATENTEnunv 9 Ian SHEET lUF 8 OUTSIDE SILO, 0N SAFETY LADDER.

, 7e T0 OPERATOR INVENTORS RICHARD L. WEAVER BENJAMIN K. SMOKERATTORNEYS PATENTEDin'v 9197i SHEET 5 0F 8 INVENTORS RICHARD L. WEAVERBENJAMIN K. SMOKER ATTORNEY 5' PATENTEBuuv 9 lsn 3,619, 13 1 sum 5 OF 8INVENTORS RICHARD L, WEAVER BENJAMIN K. SMOKER ATTORNEYS PATENTEDuuv 9l9?! 3.619.431

SHEEI 7 0F 8 INVENTORS RICHARD L. WEAVER BENJAMIN K. SMOKER L I IATTORNEYS sum 8 OF 8 FIG. 22

mvmons RICHARD L WEAVER Fax ATTORNEYS BENJAMIN K- SMOKER f qv 5PAIENTEflnnv 9 IHTI SPECIFICATION This invention relates to a system forconstructing monolithic silos or other concrete structures havingannular walls. While systems involving movable forms are well known, thelarge silos being constructed today have presented problems which arequite different from those faced when the prior systems were developed.

A system today must meet labor and material requirements. For example,it is no longer practical to mix concrete atthe site; the concrete mustbe purchased in about 6, cubic yard batches. This material should bepoured as quickly as possible to produce the best possible wall.Efficient and expeditious pouringalso reduces the cost of concrete. Thesystem must, be designed to accept qualifiedpersonnel with a minimum oftraining and with a high degree of safety. The apparatus must be well'engineered and designed to minimize the labor required and the chance ofpossible error in operation.

This invention provides a system suitable for. erecting silos ofdiameters up to 24.feet-and more, the silos rising to a height of 60 to70 feet or more. The, system is designed-for 2 or 3 operators. Thesystem accepts standard ready-mix concrete truck batches in the amountof 6 yards or more.

A ring mold about 4 feet high and of the desired silo diameter iserected on a baseand filled. Two more molds arethen similarly erectedand filled to form a three tiered mold unit. During this process a cranescafiold is erected within the molds and, when desired, supportedpreferably by nine equiangular radial arms on horizontal ledges on theinner face of a mold. When the crane scaffold is mounted on the topmold, it is about'l2 feet above the base and is supported solely by theinner formsof the molds. Preferably, the inner form of each mold isdesigned to produce protrusions or mounds onthe inner wall of the silowhich serve to support the rather considerable weight of the scaffoldand operators. Theoperators and scaffoldused for erecting a 24 footdiameter silo weigh about 4,000 pounds.

The system is designed to enable the dismantling of the bottom moldafter the other two upper molds have been erected and .filled. Usually,with optimum concrete handling, a mold can be filled in the morning anddismantled'in the afternoon. The bottom outer form is moved first andthen the bottom inner mold is moved in predetermined length sections.

Since the top mold usually contains concrete which hasnot hardened orset to any significant degree when the bottom mold is transferred, thecrane-scaffold is supported substantially entirely by the middle moldinner form. The importance of sound supporting engagement of the middleinner form with the silo inner'wall will therefore be appreciated.

After the transferred mold has been assembled, thecrane scaffold israised by three jib cranes on the scaffold which are sequentiallyoperated to lift the scaffold incrementally through the 4 feet to theupper portion of the newly erected inner form. The jib cranes supportthe weight of the crane scaffold during-this lifting step on the topedge of the newly erected inner form.

The radial anns of the scaffoldhave feet whichautomatically move intoseating engagement with the ledges when the scaffold is raised. Thesefeet are operatively connected to,

safety means arranged to support the scaffold ,on the inner form if aradial arm or jib crane should fail.

These and further objects and advantages of the present invention willbecome more apparent upon reference to the following specification,appended claims and drawings wherein:

FIG. 1 is a top plan view of the system showing the basic structure;

FIG. 2 is a side view taken on line 2-2 of FIG. 1 showing the cranescaffold supported on a ledge of a top mold;

FIG. 3 is a top plan view on reduced scale showing a semicircularportion of the outer form of the bottom mold of the three tieredmoldunit, beinglifted by the jib cranes;

FIG. 4 is a side view showing the outerform portion during lifting withthe outer form shown in phantom lines in its final raised position;

FIG. 5 shows the concrete reinforcing means which is then fabricated forthe concrete wall;

FIG. 6 is a side view showing asection of the bottom inner 1 form incondition for dismantling by use of a trolley and raising by a jib cranethrough the space between the crane scaffold and the top inner form asshown in phantom lines; FIG. 7 is a detail of the trolley wheels on thering track;

FIG. 8 is aside view showing the initial incremental raising movement ofthe crane scaffold by the jib cranes;

FIG. 9 is a side view showing the concrete pouring step;

FIG. 10 is a perspective view showing the saddle used when lifting thescaffold;

FIG. 11 is a perspective view ofthe form engaging means, a foot beingshown which seats on a ledge of the inner form;

FIG. l2'is a view taken on line 12-12 of FIG; 8;

FIG. 13 is a view taken on line 13-13 of FIG. 2;

FIG. 14 is a view taken on line 14-14 of FIG. 2 showing, as does FIG.13, details of the floorsupport;

FIG. 15 is a perspective view of an innerform section;

FIG.- 16 is an enlarged view showing the connection means for the innerform sections;

FIG. 17 is a vertical cross-sectional view of the inner form sectionwith phantom lines. showing the bulging, distortion produced by. theconcrete; 7

FIG. 18 is a perspective view of an outer fonn section;

FIG. l9yis anenlarged view showing the connection means for the outerform sections;

FIG. 20 is a vertical section of the outer form section;

FIG. 2lshows the cart;

FIG. 22 is a side view in section showing a safety cage and net;

FIG. 23 is aperspective view of the ladder; and

FIG. 24 isa perspective view of a modified section for the inner mold.

FIGS. 1 and-2 show the system following the pouring of concrete into thetop mold of a previously erected vertical stack of similar ring molds,concrete reinforcement rod 16 extending upwardly from the top of thepoured annular concrete wall 17. The system shown uses nine radial arms22 and this is satisfactory for a silo of about 20 feetin diameter. Forsilos l6 feet in'diarneter, 7 radial arms are used; and for silos 24feet in diameter, IOradial arms are used.

Preferably the system includes a three tiered mold unit M and a cranescafiold S, the crane scaffold including:

a center post 21; radial arms 22, nine such arms being shown radiatingas spokes from the center post 21 and each including a radial truss 23;a form engaging means or foot 24. and a depending support arm 25 for thetrolley monorail 26; an annular deck 29 made up of substantiallytrapezoidal deck segments 30 connected to the radial arms 22; three jibcranes 27 rotatably mounted on the center post 21; a hydraulicallypowered concrete cart 28 rotatably mounted on the center post 21; aframe 3] which can be seated on the top mold and having a brace32extending to the center post 21, this frame 31 being usedwhen concreteis raised from ground level up the outside of the silo; a hydraulicpower unit 33 mounted on the radial anns 22 near the center post 21- forsupplying hydraulic power throughv lines not shown to each jib crane 27and the hydraulically driven concrete cart 28, the power unit 33including. an electric motor, pump, and oil reservoir thereby requiringonly an electrical cable connection to a power source on the ground.

The system as shown in FIGS. 1-4 is in condition for the raising of thebottom mold. By hanging a ladder over the outside of the mold unit M, anoperator can climb down to the bottom outer form 34 and divide it intosemicircular portions 35 and 36 as seen in FIG. 3, one of -thesemicircular portions 35 being shown in FIG. 4 while being lifted to atop position (shown in phantom lines) by the three jib cranes 27.

When the other semicircular portion'36 of the outer form 34 has beenraised and connected to portion 35 as well as the subjacent outer form37, an annular concrete reinforcing means 38 is erected on thereinforcement rods 16, as seen in FIG. 5.

The next step is the transfer of the bottom inner form 40. FIGS. 6 and 7show the trolley 41 in position for enabling an operator toprogressively dismantle the bottom form 40 into arcuate sections 42(FIG. of predetennined length which are lifted by a single jib crane 27upwardly through the rather restricted space between the top tier innerform 43 and the floor segment 30. The passage of a section 42 through arestricted space is shown in phantom lines in FIG. 6.

The sections 42 are then assembled as a rigid inner form 40 on top ofthe inner form 43 and the thus formed new top mold is now ready toreceive concrete.

Prior to the concrete pouring step, however, the crane scaffold S islifted from a seated position on inner form 43 (FIG. 2) to a seatedposition on the newly fon'ned top inner form 40. FIG. 8 shows jib crane27 lifting the crane scaffold S with the entire weight of the cranescaffold being supported by the inner forms 40, 43 and 45 through thepulley saddle 50. Preferably, the hydraulic power unit 33 is designedwith a capacity to operate only one single jib crane at a time, therebyreducing the weight of this unit. Each of the three cranes is thereforeseparately and sequentially operated to incrementally lift the cranescaffold S through the distance of four feet to the new seated positionon inner form 40.

FIG. 9 shows the concrete pouring step whereby a concrete bucket 46 ofabout 400 pounds capacity is hoisted by a ground based power unit (notshown) into dumping relationship with cart 28. When filled, the cart 28is hydraulically driven by power unit 47 around the deck 29 to fill thetop mold of mold unit M as quickly and evenly as possible.

The cycle is then repeated until the desired silo height has beenreached at which time provision is made in the top mold for forming roofbeam slots or notches in the top of the concrete wall. The outer formsare lowered to the ground in semicircular portions 35 and 36. Support ofthe crane scaffold S is transferred to the top of the silo wall and theinner form sections 42 are dismantled, raised and then lowered outsidethe silo wall. The crane scaffold S is then lowered inside the silo anddismantled into parts which are of such size that they pass throughnormal silo bottom access openings.

Preferably, metal ladder rungs are cast in place in the outside wallduring the wall formation. Also a vertical access passage or bay wall110 may be provided by utilizing, as seen in FIG. 1, outer form sections48 of the desired shape and core member 49 which coacts with an innerform section 42 to define the substantially semicircular bay wall 110protruding outwardly from the main annular wall 17.

The apparatus for erecting an annular wall 17 for a silo or the likewill therefore be understood as including a vertical stack of ring moldsM wherein the inner form 40 of each mold has an inwardly extending ledgemeans or ledges 60 about Ht inches wide for supporting the cranescaffold S. The crane means 27 in the form of three jib cranes 27enables the raising of the bottom outer form 34 to a top seated positionon the remaining outer forms as well as a similar raising operation forthe inner form 40. Means, such as the pulley saddle 50, are provided forsupporting the crane scaffold S through the crane means 27 on the newlyerected top inner form 40. In the lower part of the silo the bay wall110 is usually omitted; an outer form about 42 inches in horizontalarcuate length is substituted therefor.

Preferably the inner forms 40 include molding means for formingprotuberances or mounds on the inner surface of the silo wall forinterlocking support of the inner form. In the modification shown inFIGS. 15-17, the molding means is provided by a reinforcing frame 61 onthe inner form which defines a plurality of main plate portions 62 whichare distorted, that is, flexed within their elastic limit, by the weightof the concrete poured in the mold to define mounds 63 (FIGS. 2 and 17)on the wall for interlocking support of the inner forms 40. Thecombination of the reinforcing frame 61 and main plate portions 62 isvariable to enable the production of mounds of the desired pattern andsize. Mounds having a surface area of 18 square inches and which extendinwardly about 5% to I inch have been found to be satisfactory.

When the concrete is poured, the outer form is placed under tension andvery little distortion of the outer form takes place. The inner form,however, is placed under severe compression and this phenomenon isutilized for distortion of main plate portions 62 for supporting theapparatus. Because the reinforcing frame 61 of the inner form 40includes abutting side flanges, spacing connector means 65, such as thethree connector means 65 shown at the left portion of FIG. 15, areutilized at a vertical joint between inner sections 42. These spacingconnector means 65 can be knocked out of place after removal of lockingpin 66 and thereby free an inner form section 42 for dismantling.

As seen in FIG 2, the foot 24 of radial arm 22 is seated on ledge 60 andpresses against the inner section of form 42 to produce a wedged seatingof the foot. In this fashion the inner fonn is reinforced and thescaffold S is firmly seated thereon. Preferably the foot 24 is pivotallymounted on a rod 66, as seen in FIGS. 11 and 12, which is telescopicallyreceived and locked by pin 67 within the radial truss 23 to enable aradial adjustment of about six inches to insure a wedged seating action.

A safety means 70 is provided in the form of an outwardly and downwardlyextending safety bar 70 positioned for engagement with the bottomseating flange 71 of the inner form. As seen in FIG. 2, this bar 70assumes a position just above the seating flange 71.

Each jib crane 27, as seen in FIG. 8, includes a main member 73 and anupper stay element 74 rotatably mounted on center post 21. A hydraulichoist 75 is mounted on the outer portion of the main member 73 and ajack leg 76 is pivoted to the hoist 75 for seating engagement with a lug77 (FIG. 11) on a radial truss 23 when the scaffold is being lifted.

Referring now to details of the ring molds, FIGS. 15-20 show each innermold section 42 as including a main plate 81 having a smooth mold face82 and vertical side flanges 83 for abutting connection by lugs 84 whichpass through flange holes 85 and are locked in place by wedge pins 86.Chains 87 connect all connecting means to the sections.

Inner section 42 of FIG. 15 shows the reinforcing frame 61 as includingside flanges 83 and full length top and bottom seating flanges 71, topand bottom bands 88, four equally spaced intermediate U-channels 89, and3 equally spaced intermediate vertical members 90. The reinforcing framedefines 20 distortable main plate portions 62. The ledge means 60 isformed by ledge 60 extending horizontally from an upper comer of section42 with a vertical bar 91 extending to the top flange 7 I to define ahousing for a foot 24. FIG. 16 shows finger 92 clamping horizontalflanges 71 together with a keeper pin 93 holding the finger in place. I

The outer mold section 80 is slightly larger than the inner mold section42 and includes (FIGS. 18-20) a main plate 95, vertical side flanges 96with similar connecting means 97, horizontal top, intermediate, andbottom bands 98, and horizontal seating flange elements 99 at eachcorner which extend a short distance of up to a foot or more from theside flanges 96.

The horizontal edges of the outer sections 80 are connected by bottomL-bars 100 which pivot to a position inside of and under top horizontallatches 101. The horizontal portions 102 of the L-bars can support alower outer section; this is important when the bottom outer fonn isdivided into semicircular portions as seen in FIG. 3. To preventsidewise disengagement the left-hand latch 101 in FIG. 18 opens to theright to accept a clockwise pivoting L-bar 100.

Referring now to FIG. 8, it will be seen that the foot 24 is biased intoseated position by tension spring 105. While a separate spring could beused, spring 105 is connected also to safety bar 70 for urging the barinto engagement with the inner form 43 just above the bottom flange 71.

The deck segments 30 seat in troughs 106 on the radial trusses 23 asseen in FIGS. 13 and 14. A locking device 107 shown in FIG. 13positioned inwardly of outer trough 106 prevents the outermost decksegment 30 from tilting.

The trolley monorail 26 is supported by support arm 25 and also byhangers 108 seated on and depending from the deck 29 as seen in H6. 4.This arrangement also serves to maintain the deck segments 30 in thetroughs 106.

Preferably the concrete is pumped upwardly by pump 199 (FIG. 6) througha flexible conduit 200 and through the internal bore of the center post21 (about 3%" in diameter) from which it is directed into a flexibledischarge pipe 201. This concrete delivery system would replace the cartsystem previously discussed. The pump 199 could be located at groundlevel.

Preferably each arcuate section of the inner form has a ledge 60 whichincludes an outwardly projecting portion for engagement by the liftingcable 202 with cable hook 203 com nected to the angle brace 205 (FIG.6). As will be seen in the dotted line showing of FIG. 6, the balance ofthe section is such that it always tends to pivot the bottom surface ofthe cable engaging ledge 60 into engagement with the cable 202. In use,the cable 202 is placed under the ledge 60 as shown in FIG. 15, and thehook 203 connected, following which the section is moved inwardly andthen allowed to swing by gravity into the position whose in dotted linesin FIG. 6, for passage upwardly between the scaffold and the lower innerform. Proper dimensional relationships can be established whereby verylittle guidance by the operator is required.

- Various safety devices can be employed, and it is preferred that anouter safety cage 210 as shown in FIGS. 22 and 23 be used. The cage 210hooks over the top of the forms with the safety chain 211 coupled to theinner fonn or the scaffold. The safety cage, preferably, is about 16feet long with suitable protective caging in arcuate form and a solidbottom member. Internally, safety devices are provided, and, as seen inFIG. 22, a full circular net 212 is provided below the trolley 41. Thenet 212 is mounted on an annular, rigid expander ring 214 which issuspended from the crane scaffold by suspension wires 215. The centerportion of the net 212 is connected to the bottom of the center post 21.Further, it is sometimes preferable for the operators to vacate theplatform while it is raised, and to accommodate this, a control rope 216(FIG. 8) is provided for the valve control of the hydraulic hoist 75 oneach jib crane, this control rope passing over the pulley 217 outwardlyto the fonns on which the operators will support themselves duringscaffold elevation. The previously discussed cage 210 may also be usedfor the operators during this elevation.

This system of silo construction enables the production of a cylindricalsilo having accurate predetermined dimensions, this being particularlyimportant when bottom unloaders of the radial sweeping auger type areemployed. The spokes of the scaffold press the inner forms outwardly andmaintain the desired dimension.

Preferably, on the inner forms the braces 89 are U-channels, this beingparticularly important on large diameter silos such as 24 feet. WhenU-channels are employed, the vertical elements 90 can be eliminated.

FIG. 24 shows a modified inner form section involving two sheet metalplates 220-221 welded together with swinging levers 223 and 224connected at the welded joint. A cable 225 is then hooked to side chains226 which are welded to the plates and the lever 223 is then swung outto produce the desired curvature. By changing the connection with thechains, various curvatures can be produced.

While the invention has been described with reference to certainembodiments, they are to be considered illustrative rather thanlimiting, and it is intended to cover all further embodiments that fallwithin the spirit and scope of the appended claims.

We claim:

1. A method of constructing a monolithic cylindrical structure ofconcrete or the like utilizing a plurality of ring molds, each moldhaving an inner form and an outer form, and a crane scaffold comprising:

forming a vertical stack of the ring molds and filling the molds withconcrete or the like,

mounting the crane scaffold on the top ring mold by seating it insupported relation on the inner form thereof,

moving the bottom ring mold, after the top ring mold has been filled, toa seated position on said top ring mold by dismantling the outer form ofthe bottom ring mold into sections and lifting the sections by the cranescaffold upwardly to a top seated position on the remaining outer formsand then dismantling the inner form of the bottom ring mold intosections and lifting the sections by the crane scaffold upwardly betweenthe inner form of the top ring mold and the crane scaffold into place onthe top ring mold,

then transferring support of the crane scaffold from the inner form ofthe top ring mold to the inner form of the newly positioned ring moldand lifting the crane scaffold from its initial position on said innerfonn to a similar seated position on the inner form of the newlypositioned ring mold.

2. In a method as defined in claim 1 and wherein the inner face of saidcylindrical structure is formed with protrusions by the inner forms,wherein the placement of the inner mold sections on the top inner formsincludes the step of anchoring the inner forms in place for supportingthe weight of the crane scaffold.

3. In a method as defined in claim 1 and including lifting concrete orthe like to a cart supported at the outer periphery of the scaffold forrotation about the center of the scafi'old, moving said cart around thescaffold and pouring concrete or the like from the cart into the mold.

4. in a method as defined in claim 1 and wherein the lifting of saidcrane scafiold is accomplished by raising the periphery of the cranescaffold at each of three equi-angular locations a predetermineddistance at a time.

5. in an apparatus for erecting a monolithic annular wall for a concretesilo or the like, comprising:

a vertical stack of ring molds, each mold including an annular innerform and an annular outer form, inner form having inner ledge means andbeing made up of arcuate sections, a crane scaffold having means carriedthereby for engagement with said inner form only and for seating saidscaffold on said ledge means of an inner form only, said scaffold beingprovided with crane means for raising the bottom outer form to a topseated position on the remaining outer forms and for raising the bottominner form to a top seated position on the remaining inner forms, andmeans for lifting said crane scaffold onto the ledge means of thetransferred inner form.

6. In an apparatus as defined in claim 5 wherein the inner form includesmolding means for forming protuberances on the inner surface of the wallfor interlocking vertical support of the inner form.

7. in an apparatus for erecting a monolithic annular wall for a concretesilo or the like, comprising: a vertical stack of ring molds, each moldincluding an annular inner form and an annular outer form, said innerform having inner ledge means and being made up of arcuate sections, acrane scaffold carried by said inner form and being seated on said ledgemeans of an inner form and having crane means for raising the bottomouter form to atop seated position on the remaining outer forms and forraising the bottom inner form to a top seated position on the remaininginner forms, and means for lifting said crane scafiold onto the ledgemeans of the transferred inner form, and wherein the inner form includesmolding means for forming protuberances on the inner surface of the wallfor interlocking vertical support of the inner form, and wherein eachsection includes a main plate having a smooth mold face and wherein saidmolding means includes a reinforcing frame fixedly connected to theother face of the main plate defining a plurality of main plate portionseach having predetermined distortion characteristics and which comprisemeans responsive to the weight of the concrete which forms a wall forlaterally distorting under the weight of concrete in a wall being formedand for defining laterally protruding mounds on the concrete wall forinterlocking vertical support of the inner form.

8. in an apparatus as defined in claim 7 and including spacing connectormeans between an adjacent pair of inner sections of an inner form tomaintain the sections spaced apart under the compression force of theconcrete thereby to facilitate dismantling of the inner form.

9. In an apparatus as defined in claim 12 and wherein said means forautomatically engaging includes radial arms having feet pivotallymounted at the outer ends thereof for seating on said ledge means, saidfeet being mounted for pivoting downwardly on vertical movement upwardlyagainst a higher ledge means to enable passage thereby and forsubsequent seating of the scaffold on a higher inner form,

10. In an apparatus as defined in claim 12 and wherein said cranescafi'old includes as safety means extending downwardly and outwardlyinto engagement with an inner form for supporting engagement therewithupon predetermined downward movement of the crane scaffold.

ll. ln an apparatus for erecting a monolithic annular wall for aconcrete silo or the like, comprising:

a vertical stack of ring molds, each mold including an inner form and anouter form defining an annular space therebetween, each form being madeup of substantially rigid arcuate sections, each section having a mainplate having a smooth mold face and vertical side flanges for abutmentwith flanges of horizontally adjacent sections, side connection meansfor connecting abutting side flanges to produce a rigid annular form,

each outer section having a top band, an intermediate band, and a bottomband extending horizontally between said side flanges, top and bottomseating flange elements extending horizontally from said side flangesforabutment with similar flange elements of vertically adjacent outersections, first connection means at the top band and the bottom band forconnecting vertically adjacent sections,

each inner section having a top band, 4 intermediate U- channels and abottom band extending horizontally between the side flanges, full lengthtop and bottom seating flanges and three intermediate verticalreinforcing members to define 20 main plate portions which, whendistorted by concrete, belly inwardly to produce supporting mounds onthe inner face of the silo wall, each inner form having a horizontalledge at one top comer just below the top seating flange and a verticalbar connecting one end of the ledge thereto, the other end of the ledgebeing connected to the side flange, second connection means at the topand bottom seating flanges for connecting vertically adjacent sections,said inner form including spacing connector means at a vertical jointbetween side flanges of adjacent sections adapted to keep the flangesapart during compression of the inner form when the mold is filled withconcrete thereby to facilitate dismantling of the inner form intosections,

a crane scaffold including a center post, radial arms extendingsubstantially horizontally from said post, each radial arm including aradial truss rigidly connected to the center post and a form engagingmeans which includes a rod telescopically received within the truss foradjustable positioning thereof and a foot pivotally mounted on ahomontal axis between its ends on the rod such that when its outer endseats on a ledge of an inner form, its inner end seats on the top of therod, a safety bar pivotally mounted on and depending from the truss, atension spring connecting 881d bar and the inner end of said foot tobias said inner end toward said rod and said safety bar toward saidinner form, the bottom end of said safety bar being positioned justabove the bottom seating flange of the inner form for supportingengagement therewith if the foot support should fail,

deck segments mounted in radial troughs on the trusses and defining anannular deck and having outer edges which define an opening with theinner section of sufficient size to allow passage of an inner section ina tilted position,

a circular track suspended from the trusses and the deck segments, atrolley suspended from said track for movement around the inner form forenabling dismantling of sections thereof,

a cart connected to said center post for rotation around said annulardeck and having a discharge chute extending into the mold,

three jib cranes, each jib crane having a main member rotatably mountedon said center post and extending upwardly therefrom and an upper stayelement connected to the outer end of the jib crane and rotatablyconnected to the center post above said main member, a hydraulic hoistmeans on the main member,

means for vertically moving the crane scaffold by said jib cranesincluding a jack leg extending from each jib crane to a lug on a radialtruss and a pulley saddle for the hoist means seated on the top seatingflange of the inner form.

12. In an apparatus for erecting a monolithic annular wall for aconcrete silo or the like, comprising a vertical stack of ring molds,each mold including an annular inner form and an annular outer form,said inner form having inner ledge means and being made up of arcuatesections, a crane scafiold seated on said ledge means of an inner formand having crane means for raising the bottom outer form to a top seatedform position and for raising the bottom inner form to a top seated formposition, and means for lifting said crane scaffold into seated positionon the ledge means of the transferred inner form, including meanscomprising portions of said crane scafiold for automatically engagingsaid ledge means in scaffold-seating relation in response to upwardmovement of the scaffold, as the scaffold is moved to the level of saidledge means.

13. The apparatus of claim 12, wherein said crane scaffold is supportedthrough said crane means on the newly erected top inner form during thelifting operation.

14. The apparatus of claim 5, wherein said crane scafiold is supportedthrough said crane means on the newly erected top inner form during thelifting operation.

15. The apparatus of claim 5, wherein said ledge means comprise inwardlyextending lips.

16. The apparatus of claim 9, wherein each section includes a main platehaving a smooth mold face and wherein said molding means includes areinforcing frame fixedly connected to the other face of the main platedefining a plurality of main plate portions which are constructed tohave distortion characteristics such that they are distortable inwardlyby the weight of the concrete which forms a wall to define mounds on thewall for interlocking vertical support of the inner form, wherein saidfeet are sized to comprise means for wedged engagement of said scaffoldwith said main plate in the seated condition of said scaffold with itsfeet on said ledge means.

2. In a method as defined in claim 1 and wherein the inner face of saidcylindrical structure is formed with protrusions by the inner forms,wherein the placement of the inner mold sections on the toP inner formsincludes the step of anchoring the inner forms in place for supportingthe weight of the crane scaffold.
 3. In a method as defined in claim 1and including lifting concrete or the like to a cart supported at theouter periphery of the scaffold for rotation about the center of thescaffold, moving said cart around the scaffold and pouring concrete orthe like from the cart into the mold.
 4. In a method as defined in claim1 and wherein the lifting of said crane scaffold is accomplished byraising the periphery of the crane scaffold at each of threeequi-angular locations a predetermined distance at a time.
 5. In anapparatus for erecting a monolithic annular wall for a concrete silo orthe like, comprising: a vertical stack of ring molds, each moldincluding an annular inner form and an annular outer form, inner formhaving inner ledge means and being made up of arcuate sections, a cranescaffold having means carried thereby for engagement with said innerform only and for seating said scaffold on said ledge means of an innerform only, said scaffold being provided with crane means for raising thebottom outer form to a top seated position on the remaining outer formsand for raising the bottom inner form to a top seated position on theremaining inner forms, and means for lifting said crane scaffold ontothe ledge means of the transferred inner form.
 6. In an apparatus asdefined in claim 5 and wherein the inner form includes molding means forforming protuberances on the inner surface of the wall for interlockingvertical support of the inner form.
 7. In an apparatus for erecting amonolithic annular wall for a concrete silo or the like, comprising: avertical stack of ring molds, each mold including an annular inner formand an annular outer form, said inner form having inner ledge means andbeing made up of arcuate sections, a crane scaffold carried by saidinner form and being seated on said ledge means of an inner form andhaving crane means for raising the bottom outer form to a top seatedposition on the remaining outer forms and for raising the bottom innerform to a top seated position on the remaining inner forms, and meansfor lifting said crane scaffold onto the ledge means of the transferredinner form, and wherein the inner form includes molding means forforming protuberances on the inner surface of the wall for interlockingvertical support of the inner form, and wherein each section includes amain plate having a smooth mold face and wherein said molding meansincludes a reinforcing frame fixedly connected to the other face of themain plate defining a plurality of main plate portions each havingpredetermined distortion characteristics and which comprise meansresponsive to the weight of the concrete which forms a wall forlaterally distorting under the weight of concrete in a wall being formedand for defining laterally protruding mounds on the concrete wall forinterlocking vertical support of the inner form.
 8. In an apparatus asdefined in claim 7 and including spacing connector means between anadjacent pair of inner sections of an inner form to maintain thesections spaced apart under the compression force of the concretethereby to facilitate dismantling of the inner form.
 9. In an apparatusas defined in claim 12 and wherein said means for automatically engagingincludes radial arms having feet pivotally mounted at the outer endsthereof for seating on said ledge means, said feet being mounted forpivoting downwardly on vertical movement upwardly against a higher ledgemeans to enable passage thereby and for subsequent seating of thescaffold on a higher inner form.
 10. In an apparatus as defined in claim12 and wherein said crane scaffold includes a safety means extendingdownwardly and outwardly into engagement with an inner form forsupporting engagement therewith upon predetermined downward movement ofthe crane scaffold.
 11. In an apparatus for erecting a monolithicannular wall for a concrete silo Or the like, comprising: a verticalstack of ring molds, each mold including an inner form and an outer formdefining an annular space therebetween, each form being made up ofsubstantially rigid arcuate sections, each section having a main platehaving a smooth mold face and vertical side flanges for abutment withflanges of horizontally adjacent sections, side connection means forconnecting abutting side flanges to produce a rigid annular form, eachouter section having a top band, an intermediate band, and a bottom bandextending horizontally between said side flanges, top and bottom seatingflange elements extending horizontally from said side flanges forabutment with similar flange elements of vertically adjacent outersections, first connection means at the top band and the bottom band forconnecting vertically adjacent sections, each inner section having a topband, 4 intermediate U-channels and a bottom band extending horizontallybetween the side flanges, full length top and bottom seating flanges andthree intermediate vertical reinforcing members to define 20 main plateportions which, when distorted by concrete, belly inwardly to producesupporting mounds on the inner face of the silo wall, each inner formhaving a horizontal ledge at one top corner just below the top seatingflange and a vertical bar connecting one end of the ledge thereto, theother end of the ledge being connected to the side flange, secondconnection means at the top and bottom seating flanges for connectingvertically adjacent sections, said inner form including spacingconnector means at a vertical joint between side flanges of adjacentsections adapted to keep the flanges apart during compression of theinner form when the mold is filled with concrete thereby to facilitatedismantling of the inner form into sections, a crane scaffold includinga center post, radial arms extending substantially horizontally fromsaid post, each radial arm including a radial truss rigidly connected tothe center post and a form engaging means which includes a rodtelescopically received within the truss for adjustable positioningthereof and a foot pivotally mounted on a horizontal axis between itsends on the rod such that when its outer end seats on a ledge of aninner form, its inner end seats on the top of the rod, a safety barpivotally mounted on and depending from the truss, a tension springconnecting said bar and the inner end of said foot to bias said innerend toward said rod and said safety bar toward said inner form, thebottom end of said safety bar being positioned just above the bottomseating flange of the inner form for supporting engagement therewith ifthe foot support should fail, deck segments mounted in radial troughs onthe trusses and defining an annular deck and having outer edges whichdefine an opening with the inner section of sufficient size to allowpassage of an inner section in a tilted position, a circular tracksuspended from the trusses and the deck segments, a trolley suspendedfrom said track for movement around the inner form for enablingdismantling of sections thereof, a cart connected to said center postfor rotation around said annular deck and having a discharge chuteextending into the mold, three jib cranes, each jib crane having a mainmember rotatably mounted on said center post and extending upwardlytherefrom and an upper stay element connected to the outer end of thejib crane and rotatably connected to the center post above said mainmember, a hydraulic hoist means on the main member, means for verticallymoving the crane scaffold by said jib cranes including a jack legextending from each jib crane to a lug on a radial truss and a pulleysaddle for the hoist means seated on the top seating flange of the innerform.
 12. In an apparatus for erecting a monolithic annular wall for aconcrete silo or the like, comprising a vertical stack of ring molds,each mold including an annular inner form and An annular outer form,said inner form having inner ledge means and being made up of arcuatesections, a crane scaffold seated on said ledge means of an inner formand having crane means for raising the bottom outer form to a top seatedform position and for raising the bottom inner form to a top seated formposition, and means for lifting said crane scaffold into seated positionon the ledge means of the transferred inner form, including meanscomprising portions of said crane scaffold for automatically engagingsaid ledge means in scaffold-seating relation in response to upwardmovement of the scaffold, as the scaffold is moved to the level of saidledge means.
 13. The apparatus of claim 12, wherein said crane scaffoldis supported through said crane means on the newly erected top innerform during the lifting operation.
 14. The apparatus of claim 5, whereinsaid crane scaffold is supported through said crane means on the newlyerected top inner form during the lifting operation.
 15. The apparatusof claim 5, wherein said ledge means comprise inwardly extending lips.16. The apparatus of claim 9, wherein each section includes a main platehaving a smooth mold face and wherein said molding means includes areinforcing frame fixedly connected to the other face of the main platedefining a plurality of main plate portions which are constructed tohave distortion characteristics such that they are distortable inwardlyby the weight of the concrete which forms a wall to define mounds on thewall for interlocking vertical support of the inner form, wherein saidfeet are sized to comprise means for wedged engagement of said scaffoldwith said main plate in the seated condition of said scaffold with itsfeet on said ledge means.